Top 20 String qstns

Question 1

1. What is String in Java? Is it a datatype?

Answer 1

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Question 2

2. What is the difference between String in C language and String in Java?**

Answer 2

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Question 3

3. What is the String pool in Java?**

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Question 4

4. Why String is immutable?**

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Question 5

5. How many objects will be created from the following code?**

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Question 6

6. What is theintern()method?**

Answer 6

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Question 7

7. What is the difference between the**StringandStringBuffer?

Answer 7

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Question 8

8. What is the difference between the**StringBufferandStringBuilder?

Answer 8

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Question 9

9. Can we compare String using the==operator? What is the risk?**

Answer 9

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Question 10

10. What are the ways to compare string?**

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Question 11

11. What is the use of thesubstring()method?**

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Question 12

12. How to check if the String is empty?**

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Question 13

13. What is theformat()method in Java String? What is the difference between theformat()method and theprintf()method?**

Answer 13

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Question 14

14. Can you say String is ‘thread-safe’ in Java?**

Answer 14

Yes, we can say that the string is thread-safe.

As we know, String is immutable in Java. That means once we created a string, we can not modify it afterword. Hence there is no issue of multiple threads accessing a string object.

Question 15

15. Why most of the time string is used asHashMapkey?**

Answer 15

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Question 16

16. Can you convert String to Int and vice versa?**

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Question 17

17. What is thesplit()method?**

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Question 18

18. What is the difference between"Gaurav Kukade".equals(str)andstr.equals("Gaurav Kukade")?**
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Answer 18

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Question 19

19. Can we use a string in switch case in java?**

Answer 19

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Question 20

20. How string concatenation using the+operator works in Java?**

Answer 20

+operator is the only overloaded operator. You can use it for both adding two numbers as well as for string concatenation purposes.

If you are using the Java version 1.5 or above, string concatenation internally uses the`append()`method of the`StringBuilder`. And for versions lower than 1.5, it uses the`append()`method of the`StringBuffer`class